A spindle motor performs the function of rotating a disk to enable an optical pickup which linearly reciprocates in an optical disk drive (ODD) to read data recorded on the disk.
In general, a compact disk is formed with a gap of 1.7 μm between tracks on which data is recorded, while a Blu-ray disk (BD) is formed with a gap of 0.7 μm between tracks on which data is recorded. The gap between the tracks in the BD is rather narrow than that of the compact disk, whereby the BD can store more data over the compact disk.
Furthermore, in order to read and write on the BD in a short period of time, a rotating speed of BD is faster than the compact disk. A spindle motor configured to rotate the BD includes a turn table coupled to a rotation shaft and disposed with the BD, and a center cone coupled to the rotation shaft. The BD is coupled to the center cone and arrange on the turn table. An inner periphery of the BD coupled to the center cone is brought into contact with an entire outer periphery of the center cone.
In a case the rotation shaft of the spindle motor rotates at a speed exceeding 10,000 rpm while the inner periphery of the BD coupled to the center cone is brought into contact with an entire outer periphery of the center cone, part of the BD surfaces from the turn table due to resonance phenomenon, whereby data read error and write error are generated.